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I w. CUMBERLAND.

Making White Lead. I y N0.- 767. I Patented June 7, 1838.

WM. CUMBERLAND, on NE YORK, IN. Ya

MANUFACTURING A WHITE rTGMENT To an USED as A SUBSTITUTE Ton wizrm LEAD.

Specification of Letters'Patent No. 767, dated June 7, 1838.

To all whom it may concern:

Be it known that I, WILLIAM CUMBER- LAND, of the city of New York, in the State of New York, have invented a new and improved process for manufacturing a white pigment with a basis of lead, to be used as a substitute for white lead for painting when ground in oil or in any other fluid, according to the nature of the work to be performed;

and I do hereby declare that the following is a full and exact description thereof.

The first operation in preparing my white pigment is to obtain a protoxid of lead by triturating metallic lead in water, to which, in general, I add a portion of caustic soda, to facilitate the process. This production of a protoxid of leadbytriturationis now practised in some manufactories of carbonate of lead, and is not of my invention, but the means which I have adopted of effecting it facilitates the process, and is as follows: I granulate the lead by fusing it, and pouring it into water, in the ordinary way. This lead I put into a triturating vessel, differing in construction from the cylinders usually employed. This vessel is somewhat in the form of a saucer, or bowl, so as to expose a considerable surface to the action of the atmosphere; it may be of cast iron, and of such size as shall adapt it to the quantity of work to be performed. An iron shaft passes through the axis of this vessel, and is attached to it, so that they may revolve together. The shaft is inclined twenty five degrees, more or less, from the perpendicular, and motion is communicated to it in any convenient manner. Into the vessel, so constructed, I put my grandulated lead, with as much water as may be requisite,-adding about an ounce of caustic soda to every four or five gallons of water. The revolution of the axis, combined with its inclination and that of the triturating vessel causes the granulated lead to roll over, and thus produces the necessary friction among its particles, and also the requisite exposure to the influence of the atmosphere, in the most advantageous way. This operation is usually kept up for about twelve hours when the oxid of lead which has been found, and which is of a pale yellow color, is separated from the metallic lead, and well washed. During the process portions of water are added to supply any loss by evaporation, or otherwise.

The accompanying drawing represents a' machinewhich I have invented for :thisjpu-rpose. The frame work may be differently constructed, all that is necessary being so'to form it that the shaft upon which the triturating vessel is fixed, and with which it revolves, may be placed atan inclination from the perpendicular of from twenty-five to forty-five degrees, more or less.

Figure 1 represents a vertical section of the triturating vessel and its shaft. F, F,

is the body of the vessel, which has a rim G e the upper end of the shaft E E; there being V at its lower end a sill timber C, and step D. A cog or band wheel H, mav occupy any situation on the shaft, which may be found .most convenient. The shaft need not run through the vessel, but may be supported in a collar, below it. The body of the vessel may be made entirely of lead, or of any other metal, and lined with lead; its form may be varied considerably, it only being necessary that its characteristic properties be carefully preserved.

I have thus given the mode of producing the protoxids which experience has shown to be a very good one, and I believe the best; but I do not limit myself to this particular mode of forming the protoxid, but occasionally take this oxid prepared in any other way, and subject it to the subsequent operations by which the pigment in question is formed. The yellow protoxid, produced as above, or the protoxid obtained in any other way, is to be placed in a vessel, with a considerable quantity of water, and diluted sulfuric acid is then poured among it, agitating the mixture not only during the pouring, but for a considerable space of time, and it will be found that the protoxid of lead will be thereby converted into a white pigment, which is a peculiar sub-sulfate of lead, possessing properties not found in the ordinary sulfate of lead, the

acid; as from the acetate or nitrate of that;

metal; the sulfate so produced Will be a White powder, but it will not possess the body, or other properties which fit it to be substituted for the carbonate of lead in painting; While that prepared in the Way which I have indicated will be found to possess these vproperties in an eminent de- 7 gree.

What I claim, therefore, as my invention,

i and Wish to secure byLetters Patent, is

,pouring the sulfuric acid into the mixture of Water and the protoxid of lead, in the forth.

H 2. I also claim the triturating vessel constructed substantially in the Way described.

WILLIAM CUMBERLAND. Witnesses:

W. THoMPsoN,

H. B. ROBERTSON.

Vmanner, and for the purposes herein set 

